drivers/hwmon/lm73.c

   1 /*
   2  * LM73 Sensor driver
   3  * Based on LM75
   4  *
   5  * Copyright (C) 2007, CenoSYS (www.cenosys.com).
   6  * Copyright (C) 2009, Bollore telecom (www.bolloretelecom.eu).
   7  *
   8  * Guillaume Ligneul <guillaume.ligneul@gmail.com>
   9  * Adrien Demarez <adrien.demarez@bolloretelecom.eu>
  10  * Jeremy Laine <jeremy.laine@bolloretelecom.eu>
  11  *
  12  * This software program is licensed subject to the GNU General Public License
  13  * (GPL).Version 2,June 1991, available at
  14  * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/init.h>
  19 #include <linux/i2c.h>
  20 #include <linux/hwmon.h>
  21 #include <linux/hwmon-sysfs.h>
  22 #include <linux/err.h>
  23
  24
  25 /* Addresses scanned */
  26 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4c,
  27                                         0x4d, 0x4e, I2C_CLIENT_END };
  28
  29 /* LM73 registers */
  30 #define LM73_REG_INPUT          0x00
  31 #define LM73_REG_CONF           0x01
  32 #define LM73_REG_MAX            0x02
  33 #define LM73_REG_MIN            0x03
  34 #define LM73_REG_CTRL           0x04
  35 #define LM73_REG_ID             0x07
  36
  37 #define LM73_ID                 0x9001  /* 0x0190, byte-swapped */
  38 #define DRVNAME                 "lm73"
  39 #define LM73_TEMP_MIN           (-40)
  40 #define LM73_TEMP_MAX           150
  41
  42 /*-----------------------------------------------------------------------*/
  43
  44
  45 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
  46                         const char *buf, size_t count)
  47 {
  48         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  49         struct i2c_client *client = to_i2c_client(dev);
  50         long temp;
  51         short value;
  52
  53         int status = kstrtol(buf, 10, &temp);
  54         if (status < 0)
  55                 return status;
  56
  57         /* Write value */
  58         value = (short) SENSORS_LIMIT(temp/250, (LM73_TEMP_MIN*4),
  59                 (LM73_TEMP_MAX*4)) << 5;
  60         i2c_smbus_write_word_swapped(client, attr->index, value);
  61         return count;
  62 }
  63
  64 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
  65                          char *buf)
  66 {
  67         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  68         struct i2c_client *client = to_i2c_client(dev);
  69         /* use integer division instead of equivalent right shift to
  70            guarantee arithmetic shift and preserve the sign */
  71         int temp = ((s16) (i2c_smbus_read_word_swapped(client,
  72                     attr->index))*250) / 32;
  73         return sprintf(buf, "%d\n", temp);
  74 }
  75
  76
  77 /*-----------------------------------------------------------------------*/
  78
  79 /* sysfs attributes for hwmon */
  80
  81 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
  82                         show_temp, set_temp, LM73_REG_MAX);
  83 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
  84                         show_temp, set_temp, LM73_REG_MIN);
  85 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
  86                         show_temp, NULL, LM73_REG_INPUT);
  87
  88
  89 static struct attribute *lm73_attributes[] = {
  90         &sensor_dev_attr_temp1_input.dev_attr.attr,
  91         &sensor_dev_attr_temp1_max.dev_attr.attr,
  92         &sensor_dev_attr_temp1_min.dev_attr.attr,
  93
  94         NULL
  95 };
  96
  97 static const struct attribute_group lm73_group = {
  98         .attrs = lm73_attributes,
  99 };
 100
 101 /*-----------------------------------------------------------------------*/
 102
 103 /* device probe and removal */
 104
 105 static int
 106 lm73_probe(struct i2c_client *client, const struct i2c_device_id *id)
 107 {
 108         struct device *hwmon_dev;
 109         int status;
 110
 111         /* Register sysfs hooks */
 112         status = sysfs_create_group(&client->dev.kobj, &lm73_group);
 113         if (status)
 114                 return status;
 115
 116         hwmon_dev = hwmon_device_register(&client->dev);
 117         if (IS_ERR(hwmon_dev)) {
 118                 status = PTR_ERR(hwmon_dev);
 119                 goto exit_remove;
 120         }
 121         i2c_set_clientdata(client, hwmon_dev);
 122
 123         dev_info(&client->dev, "%s: sensor '%s'\n",
 124                  dev_name(hwmon_dev), client->name);
 125
 126         return 0;
 127
 128 exit_remove:
 129         sysfs_remove_group(&client->dev.kobj, &lm73_group);
 130         return status;
 131 }
 132
 133 static int lm73_remove(struct i2c_client *client)
 134 {
 135         struct device *hwmon_dev = i2c_get_clientdata(client);
 136
 137         hwmon_device_unregister(hwmon_dev);
 138         sysfs_remove_group(&client->dev.kobj, &lm73_group);
 139         return 0;
 140 }
 141
 142 static const struct i2c_device_id lm73_ids[] = {
 143         { "lm73", 0 },
 144         { /* LIST END */ }
 145 };
 146 MODULE_DEVICE_TABLE(i2c, lm73_ids);
 147
 148 /* Return 0 if detection is successful, -ENODEV otherwise */
 149 static int lm73_detect(struct i2c_client *new_client,
 150                         struct i2c_board_info *info)
 151 {
 152         struct i2c_adapter *adapter = new_client->adapter;
 153         int id, ctrl, conf;
 154
 155         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 156                                         I2C_FUNC_SMBUS_WORD_DATA))
 157                 return -ENODEV;
 158
 159         /*
 160          * Do as much detection as possible with byte reads first, as word
 161          * reads can confuse other devices.
 162          */
 163         ctrl = i2c_smbus_read_byte_data(new_client, LM73_REG_CTRL);
 164         if (ctrl < 0 || (ctrl & 0x10))
 165                 return -ENODEV;
 166
 167         conf = i2c_smbus_read_byte_data(new_client, LM73_REG_CONF);
 168         if (conf < 0 || (conf & 0x0c))
 169                 return -ENODEV;
 170
 171         id = i2c_smbus_read_byte_data(new_client, LM73_REG_ID);
 172         if (id < 0 || id != (LM73_ID & 0xff))
 173                 return -ENODEV;
 174
 175         /* Check device ID */
 176         id = i2c_smbus_read_word_data(new_client, LM73_REG_ID);
 177         if (id < 0 || id != LM73_ID)
 178                 return -ENODEV;
 179
 180         strlcpy(info->type, "lm73", I2C_NAME_SIZE);
 181
 182         return 0;
 183 }
 184
 185 static struct i2c_driver lm73_driver = {
 186         .class          = I2C_CLASS_HWMON,
 187         .driver = {
 188                 .name   = "lm73",
 189         },
 190         .probe          = lm73_probe,
 191         .remove         = lm73_remove,
 192         .id_table       = lm73_ids,
 193         .detect         = lm73_detect,
 194         .address_list   = normal_i2c,
 195 };
 196
 197 /* module glue */
 198
 199 static int __init sensors_lm73_init(void)
 200 {
 201         return i2c_add_driver(&lm73_driver);
 202 }
 203
 204 static void __exit sensors_lm73_exit(void)
 205 {
 206         i2c_del_driver(&lm73_driver);
 207 }
 208
 209 MODULE_AUTHOR("Guillaume Ligneul <guillaume.ligneul@gmail.com>");
 210 MODULE_DESCRIPTION("LM73 driver");
 211 MODULE_LICENSE("GPL");
 212
 213 module_init(sensors_lm73_init);
 214 module_exit(sensors_lm73_exit);